The present invention relates generally to the vehicle trailers, and more particularly to improved trailers of the type adapted to dump the contents thereof, either with or without movement of the trailer body or portions thereof.
Various kinds of vehicle trailers, including those which unload or dump their contents either by gravity or by movement of the trailer body are well known; however, the present invention concerns trailers of novel construction which combine the advantages of easy unloading with numerous other advantages as will appear herein. Trailers of the invention utilize the so-called fifth wheel principle, and are particularly adapted for advantageous use with vehicles not normally intended to haul large trailers, such as pick-up trucks or other small vehicles.
In the trucking industry, the heaviest loads are normally carried by vehicles of the tractor and semi-trailer type, or in some cases, by a combination of tractor, semi-trailer, and full trailer. For various reasons, including difficulty in parking and other maneuvering, the combination of straight trucks with full trailers for heavy duty trucking is relatively rare in this country.
By semi-trailers is meant a trailer in which at least some, and usually a significant part, of the load is borne by the chassis of the towing vehicle, normally a tractor. In such constructions, one end of the semi-trailer rests above the rear axle or axles of the tractor, with the attachment and pivoting motion being accommodated by a plate and latch assembly which, by reason of its generally circular shape and central location of its pintle lock, is referred to as a fifth wheel.
The tractor and semi-trailer principle has been generally accepted as the most economical and practical solution for transporting loads which are large, heavy, or both. In the tractor and semi-trailer concept, the tractor is generally compact and mobile, while the semi-trailer accommodates the entire payload. The semi-trailer is not itself a full trailer, and hence is cheaper and simpler to manufacture than a complete trailer, which would by definition include running gear at the front as well as the rear thereof.
In the last few years, the characteristic advantages of small, open bodied vehicles, such as pickup trucks, have been taken advantage of by mounting in the beds of such trucks a "fifth wheel" assembly adapted to receive the forward part, or an extension of the forward part, of a vehicle trailer or semi-trailer. Such so-called fifth wheel pickup trucks have been used to carry loads which are much greater than those which could be accommodated merely by attaching a semi-trailer or trailer to a trailer hitch at the rear of the pickup truck or other towing vehicle.
The loads able to be carried (the "tongue weight") by a trailer hitch on a light vehicle, such as a pickup truck, are very limited because the trailer hitch is capable of carrying only a minimum load. This is true because of the moments created by the spacing between the trailer hitch and the truck axle, and because the hitch is sometimes supported only by an end part of the vehicle frame.
Because of the bed configuration of pickup trucks, however, it has been found necessary that the usual fifth wheel pickup truck semi-trailer include a goose neck or other elevated portion extending from the front of the trailer payload area to the pivot point or fifth wheel. As pointed out, the fifth wheel can support much greater tongue weight loads than can the trailer hitch, and thus the fifth wheel trailer in turn can accommodate much greater loads. In each case, a certain portion of the load appears as tongue weight, and the rest of the load is supported by the trailer wheels.
Ordinarily, fifth wheel trailers adapted for use with pickup trucks have included a relatively long goose neck or extension, because the rearward extent of the pickup body would otherwise interfere with the trailer box when turning was attempted.
As a result, many fifth wheel trailers adapted for use with pickup trucks have been much longer, and hence heavier, than would otherwise be desirable.
Referring now to another matter, there exists, in the agricultural field particularly, a demand for trailers which have a dumping capability and which are economical to make and use. Up until now, most of this demand has been met by trailers referred to as "gravity boxes", that is, trailers containing hopper-type bodies either fixed to or removably associated with a trailer chassis. Gravity boxes are desirable because they can be easily loaded with the agricultural product in question from the discharge chute of a combine, a conveyor, or the like. The gravity boxes may then be unloaded at an elevator, feed lot or other location, simply by gravity.
In other cases, such as where the nature of the crop or product being hauled requires a steep angle of inclination to induce gravity flow, fifth wheel trailers have been made which include conventional dumping mechanisms associated with rectangular box, flat bottom, type bodies. As pointed out above, however, trailers of this sort have been very long because of the clearance required between the trailer body and the truck box.
Conventional gravity boxes of the full trailer type may use shorter tongues, but full trailers are difficult to maneuver, especially during backing.
The present invention relates to a novel, compact fifth wheel trailer or semi-trailer which includes a trailer frame, a forward extension thereof, and a fifth wheel-engaging member, with the trailer body including sidewalls, a rear wall, a rearwardly inclined floor, and in one embodiment, means for tilting the box so as to further increase the inclination of the floor to achieve dumping of generally non-fluent products. In the preferred construction, the upper portion of the trailer body extends above and forwardly of the rear end portion of the associated pickup truck or other towing vehicle.
In view of the drawbacks and disadvantages of certain trailers and semi-trailers of the prior art, it is an object of the present invention to provide an improved trailer or semi-trailer unit.
A further object is to provide a trailer of the fifth wheel type which provides for improved maneuverability in use.
Another object is to provide a fifth wheel trailer capable of discharging or dumping a product contained therein, with or without the aid of a mechanism to elevate the trailer body or a part thereof.
Still another object is to provide a vehicle trailer unit having an inclined floor adapted to permit discharge of the trailer contents under the influence of gravity, with the trailer being arranged such that a portion of the body extends forwardly of the wheels and overlies a portion of the towing vehicle in use.
A further object is to provide a dumping type vehicle trailer which is adapted for advantageous combination with a towing vehicle of the pickup truck type.
Yet another object is to provide a trailer which has particular advantages and desirable characteristics for agricultural use.
Another object is the provision of a trailer which is compact and light in relation to its weight capacity.
The present invention achieves these and other objects by providing a trailer unit having a frame and means extending therefrom for engaging a fifth wheel mechanism on a towing vehicle, and a body having an inclined floor portion, with the body portion having a part adapted to extend above and forward of the rear portion of the towing vehicle. The above objects are also achieved by providing a trailer of the foregoing type which further includes means for further inclining the trailer floor for dumping the trailer contents.
The exact manner in which these objects and advantages are achieved in practice will become more clearly apparent when reference is made to the following detailed description of the preferred embodiments of the invention set forth by way of example and shown in the accompanying drawings, in which like reference numerals indicate corresponding parts throughout.